It was not an outstanding week for HF propagation with low solar flux index numbers and an elevated Kp index at times. The week started off OK with the ARRL DX CW contest. This went quite well with 15 metres open as far as the mid-west in the afternoon, even for modestly-equipped stations. But with a solar flux below 100 the bands were never going to be alight. Geomagnetic conditions were mixed as well, with two periods where the Kp index rose to five. One of these was probably due to the solar wind from an Earth-facing coronal hole, which we spoke about last week.
The trouble is there is another coronal hole on the solar surface, which will be Earth-centric on Friday. So we potentially have a geomagnetic disturbance lined up for Sunday or Monday once again.
Sunspot-wise, NOAA predicts that we may get a slight upturn with the SFI just tipping into the low 100s. But it says we can only expect a maximum of 105, so nothing to get too excited about.
But other than the aforementioned solar wind stream from a coronal hole this weekend, the prediction is for a more settled Sun with a maximum Kp Index of two.
Propquest confirms the conditions, showing that the extrapolated MUF figures—based on the Chilton ionsonde data—show a maximum of about 21MHz during the day, with very occasional openings on 24MHz at times.
We may be heading towards solar maximum, but we still have a long way to go.
VHF and up:
The weather will turn quieter for the coming week and although there will be some unsettled weather in the north and west at first, for most southern areas this weekend will start the sequence with a weak ridge of high pressure.
After a weakening front in the first part of the week, a new high will arrive and remain in control for much of next week. This could be good news for the 144MHz UK Activity Contest on Tuesday evening. Hopefully, some tropo will be left over for the RSGB 144/432MHz contest over the following weekend of 5 to 6 March, but at the moment it looks as though the high will be displaced a little to the west, leaving a colder northerly over the country and not ideal for tropo despite the pressure being fairly high.
Other modes are possible, for example, there’s always the chance of aurora and random meteor scatter. We are still in the closed-season for traditional sporadic E, and low levels of meteor activity, but it’s always worth a look at the beacons and clusters, just in case.
The Moon passed perigee today, so path losses are at their lowest, but combined with minimum declination yesterday Moon windows are short but increase throughout the week. Declination goes positive again on Friday.
144MHz sky noise is low to moderate all week, but the Sun and Moon are close to eclipse from 0900hrs Wednesday until moonset, making EME difficult, especially at VHF. (rsgb.org)
